RATIONALE: Vorinostat may may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Vorinostat may also help aromatase inhibitor therapy work better by making tumor cells more sensitive to the drug. PURPOSE: This clinical trial studies vorinostat in treating patients with stage IV breast cancer receiving aromatase inhibitor therapy.

Eligibility Criteria (must meet the following to participate in this study)

Ages Eligible for Study:

18 Years and older

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

Inclusion

Histologically or cytologically proven diagnosis of breast cancer

Stage IV disease

Patient has previously derived clinical benefit from AI or other endocrine therapy, but is no longer deriving benefit to AI therapy in the opinion of the treating investigator; patients need to stop the AI for at least one week prior to starting vorinostat treatment on this protocol

At least one site of measurable disease, as defined by the modified RECIST Criteria

ECOG performance status 0-2

Female patient is either post menopausal, free from menses for >= 2 years, surgically sterilized or willing to use 2 barrier methods of contraception (such as IUD, diaphragm, condom) to prevent pregnancy or agrees to abstain from heterosexual activity throughout the study

Female patient of childbearing potential has a negative serum or urine pregnancy test within 7 days prior to receiving the first dose of vorinostat

Female patient that is pre-menopausal must be on ovarian suppression therapy

Male patient agrees to use two barrier methods of contraception or abstain from intercourse for the duration of the study

Partial thromboplastin time (PTT) =< 1.2 times the ULN unless the patient is receiving therapeutic anticoagulation

Potassium and magnesium levels within normal limits

Calculated creatinine clearance >= 30 mL/min

Serum total bilirubin =< 1.5 X ULN

AST (SGOT) and ALT (SGPT) =< 2.5 X ULN

Alkaline Phosphatase =< 2.5 X ULN

Patient, or the patient's legal representative, has voluntarily agreed to participate by giving written informed consent

Patient has a life expectancy of at least 12 weeks

Patient is willing to continue on same AI therapy

Patient agrees to participate in imagining Protocol 7184 and is separately consented

Exclusions (conditions that would prevent participation in this study)

Exclusion

Patient has not derived clinical benefit from any previous hormonal therapy (e.g. tamoxifen or aromatase inhibitor)

Patient is currently participating or has participated in a study with an investigational compound or device within 30 days of initial dosing with study drug(s) other than the imaging protocol 7184

Patient has received an ER blocking therapy (selective estrogen receptor modulating or downregulating SERM or SERD i.e. tamoxifen or fulvestrant) within the past 6 weeks

Patient had prior treatment with an HDAC inhibitor (e.g., romidespin [Depsipeptide], NSC-630176, MS 275, LAQ-824, belinostat [PXD-101], LBH589, MGCD0103, CRA024781, etc); patients who have received compounds with HDAC inhibitor-like activity, such as valproic acid, as anti-tumor therapy should not enroll in this study; patients who have received such compounds for other indications, e.g. valproic acid for epilepsy, may enroll after a 30-day washout period

Patient is on any systemic steroids that have not been stabilized to the equivalent of =<10 mg/day prednisone during the 30 days prior to the start of the study drugs

Patient has known hypersensitivity to the components of study drug or its analogs

Type I Diabetes Mellitus; patients with Type II Diabetes Mellitus will be included as long as their glucose can be controlled to under 200 mg/dL

Patient is pregnant or breast feeding, or expecting to conceive or father children within the projected duration of the study

Patient with a "currently active" second malignancy, other than non-melanoma skin cancer and carcinoma in situ of the cervix, should not be enrolled; patients are not considered to have a "currently active" malignancy if they have completed therapy for a prior malignancy, are disease free from prior malignancies for > 5 years or are considered by their physician to be at less than 30% risk of relapse

Patients with known active viral hepatitis

Patient has a history or current evidence of any condition, therapy, or lab abnormality that might confound the results of the study, interfere with the patient's participation for the full duration of the study or is not in the best interest of the patient to participate